The goal of this project is to systematically explore the gelatinous zooplankton for antitumor and other biological activities. The following invertebrate groups will be collected: Cnidaria (hydromedusae, hydroids, scyphomedusae, siphonophores), Ctenophora, Mollusca (pteropods, heteropods, nudibranchs), and Urochordata (tunicates, doliolids, pyrosomes). Phase I will concentrate on collecting 10% of a systematic program total of 150-200 species and on evaluating the cost-effectiveness of several collection and recollection methods (bucket, trawl, and SCUBA). Samples will be extracted and screened against a panel of 5-6 human tumor cell lines. Active extracts will be further fractionated according to biological activity, and described chemically. Phase II will continue this work and the NCI will be given the opportunity to screen the collection. It is expected that new chemical entities, with important pharmaceutical activities, will be described and patented; they will be licensed to the government or pharmaceutical companies for development. The evaluation of gelatinous zooplankton represents a new opportunity for drug discovery. Only a few species have been evaluated due to the perceived technical difficulty of collecting and recollecting zooplankton in kilogram quantities. These planktonic species are likely sources of bioactive metabolites since their benthic (bottom-living) relatives have yielded many bioactive metabolites.